Stanford

Around the Bay

Heads or Tails? Both Win at B Factory Book Meeting

KEK co-editor Bruce Yabsley (right) holds up the special German coin while
BaBar co-editor Soeren Prell (left) stands ready to call "heads" or "tails." (Photo courtesy the editors of The Physics of B-Factories.)

The Physics of B-Factories, a first-of-its-kind anthology of the
B factory particle physics done by SLAC's BaBar experiment and the Belle experiment at KEK in Japan, is well on its way to completion. Last year the
book's editors held their first meeting at SLAC, and in late May they reunited for a second meeting at the KEK facility. The group discussed the progress and organization of the massive project, and used an unusual method to answer a long-standing question.

For more than a decade, Belle and BaBar raced alongside each other to explore the subatomic world of
B meson physics. The experiments simultaneously uncovered experimental evidence to support a theory that could partly explain why the matter we are made of is still around today (matter/antimatter asymmetry). This discovery made it possible for the theorists Makoto Kobayashi and Toshihide Maskawa to share the
2008 Nobel Prize in physics (along with Yoichiro Nambu). Now that the BaBar detector has completed its experimental run, and Belle is set for a possible upgrade, the two collaborations have come together to put their collective knowledge into a comprehensive book, which they hope will benefit future generations of physicists.

"It is exciting to put the complete work of BaBar and Belle into one place, and hopefully make it more accessible for the next generation of graduate students and postdocs," said BaBar Physics Analysis Coordinator emeritus and one of the book's primary editors, Soeren Prell. "And I enjoy that we have a very good working relationship with our Belle colleagues. While at KEK I finally got to see the Belle experiment, including the Belle control room and detector, and the KEKB control room."

In addition to the many organizational issues that needed to be worked
out at the meeting, the editors had to tackle another pesky problem: the two
collaborations had come up with slightly different names for some of the
values they measured. For example, both theorists and experimentalists gave
great attention to what's known as the "unitarity triangle." Being the first groups to study these things in depth, the collaborations each
chose different names for the angles of this triangle. So which notation would be used in the book? Since there was no pressing reason to use one set over the other, the group chose a lighthearted approach to settle the matter: a coin toss.

It's tails! (Photo courtesy the editors of The Physics of B-Factories.)

Belle co-editor Bruce Yabsley tossed the coin, while BaBar co-editor Adrian Bevan was ready to call out "heads" or "tails." As the specially selected German coin flew into the air, Bevan called, "heads!" The coin struck the floor, and landed… tails up! As a result,
The Physics of B-Factories will use the Belle notation for the names of the angles in the "unitarity triangle," and BaBar notation will be used in all other instances where the experiments have chosen different notations.

The Physics of B-Factories is set to be submitted for publication in mid-2012.